Exports and sectoral financial dependence: evidence on French firms during the great global crisis

The unprecedented drop in international trade during the last quarter of 2008 and the first quarter of 2009 has mainly been analysed at the macroeconomic or sectoral level. However, exporters who are heterogeneous in terms of productivity, size or external financial dependence should be heterogeneously affected by the crisis. This issue is examined in this paper by using data on monthly exports at the product and destination level for some 100,000 individual French exporters, up to 2009M4. We show that the drop in French exports is mainly due to the intensive margin of large exporters. Small and large exporters are evenly affected when sectoral and geographical specialisations are controlled for. Lastly, exporters (small and large) in sectors structurally more dependent on external finance are the most affected by the crisis. JEL Classification: F02, F10, G01financial crisis, firms’ heterogeneity, intensive and extensive margins, international trade

Optical trapping and surgery of living yeast cells using a single laser

We present optical trapping and surgery of living yeast cells using two operational modes of a single laser. We used a focused laser beam operating in continuous-wave mode for noninvasive optical trapping and manipulation of single yeast cell. We verified that such operational mode of the laser does not cause any destructive effect on yeast cell wall. By changing the operation of the laser to femtosecond-pulsed mode, we show that a tightly focused beam dissects the yeast cell walls via nonlinear absorption. Lastly, using the combined technique of optical microsurgery and trapping, we demonstrate intracellular organelle extraction and manipulation from a yeast cell. The technique established here will be useful as an efficient method for both surgery and manipulation of living cells using a single laser beam.The project has been funded by the Philippine Council for Advanced Science and Technology Research and Development PCASTRD. J. Ando acknowledges the support of the Japan Student Services Organization JASSO for the short-term student exchange promotion program

Exports and sectoral financial dependence: evidence on French firms during the great global crisis

The unprecedented drop in international trade during the last quarter of 2008 and the first quarter of 2009 has mainly been analysed at the macroeconomic or sectoral level. However, exporters who are heterogeneous in terms of productivity, size or external financial dependence should be heterogeneously affected by the crisis. This issue is examined in this paper by using data on monthly exports at the product and destination level for some 100,000 individual French exporters, up to 2009M4. We show that the drop in French exports is mainly due to the intensive margin of large exporters. Small and large exporters are evenly affected when sectoral and geographical specialisations are controlled for. Lastly, exporters (small and large) in sectors structurally more dependent on external finance are the most affected by the crisis

Subdiffraction-Limited Quantum Imaging within a Living Cell

We report both subdiffraction-limited quantum metrology and quantum-enhanced spatial resolution for the first time in a biological context. Nanoparticles are tracked with quantum-correlated light as they diffuse through an extended region of a living cell in a quantum-enhanced photonic-force microscope. This allows spatial structure within the cell to be mapped at length scales down to 10 nm. Control experiments in water show a 14% resolution enhancement compared to experiments with coherent light. Our results confirm the long-standing prediction that quantum-correlated light can enhance spatial resolution at the nanoscale and in biology. Combined with state-of-the-art quantum light sources, this technique provides a path towards an order of magnitude improvement in resolution over similar classical imaging techniques

Hochschild polytopes

The $(m,n)$-multiplihedron is a polytope whose faces correspond to $m$-painted $n$-trees, and whose oriented skeleton is the Hasse diagram of the rotation lattice on binary $m$-painted $n$-trees. Deleting certain inequalities from the facet description of the $(m,n)$-multiplihedron, we construct the $(m,n)$-Hochschild polytope whose faces correspond to $m$-lighted $n$-shades, and whose oriented skeleton is the Hasse diagram of the rotation lattice on unary $m$-lighted $n$-shades. Moreover, there is a natural shadow map from $m$-painted $n$-trees to $m$-lighted $n$-shades, which turns out to define a meet semilattice morphism of rotation lattices. In particular, when $m=1$, our Hochschild polytope is a deformed permutahedron whose oriented skeleton is the Hasse diagram of the Hochschild lattice.Comment: 32 pages, 25 figures, 7 tables. Version 2: Minor correction

Exploiting hydrogenases for biocatalytic hydrogenations

The ability of hydrogenase enzymes to activate H2 with excellent selectivity leads to many interesting possibilities for biotechnology driven by H2 as a clean reductant. Here, we review examples where hydrogenase enzymes have been used to drive native and non-native hydrogenation reactions in solution or as part of a redox cascade on a conductive support, with a focus on the developments we have contributed to this field. In all of the examples discussed, hydrogenation reactions are enabled by coupled redox reactions: the oxidation of H2 at a hydrogenase active site, linked electronically (via relay clusters in the enzyme and/or via conductive support) to the site of a reduction reaction, and we note how this parallels developments in site-separated reactivity in heterogeneous catalysis. We discuss the productivities achieved with biocatalytic hydrogenations, the scope for application of these approaches in industrial biotechnology, possibilities for scaling the production of hydrogenases, and future opportunities. Our focus is on NiFe hydrogenases, but we discuss briefly how FeFe hydrogenases might contribute to this field